Fluoran compounds

ABSTRACT

3-Dialkyl-7-phenylfluoran compounds, having the formula,   WHEREIN R1 and R2 each represents an alkyl group having from one to five carbon atoms, and a process for their preparation are disclosed. The 3-dialkyl-7-phenyl fluoran compounds are useful in pressure-sensitive and heat-sensitive copying papers.

United States Patent Kimura et al.

[ 51 Aug. 1, 1972 l FLUORAN COMPOUNDS [73] Assignee: Fuji Photo Film Co., Ltd.,

Kanagawa, Japan [22] Filed: April 16, 1970 [21] Appl. No.: 29,272

[30] Foreign Application Priority Data April 17, 1969 Japan ..44/29836 [52] US. Cl ..260/335, 106/287 [51] Int. Cl. ..C07d 7/42 [58] Field of Search ..260/335 [56] References Cited UNITED STATES PATENTS 3,442,908 5/1969 Orita et al ..260/335 Primary Examiner-Norma S. Milestone Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT 3Dialkyl-7-phenylfluoran compounds, having the formula,

wherein R and R each represents an alkyl group having from one to five carbon atoms, and a process for their preparation are disclosed. The 3-dialkyl-7-phenyl fluoran compounds are useful in pressure-sensitive and heat-sensitive copying papers.

1 Claim, No Drawings FLUORAN COMPOUNDS FIELD OF THE INVENTION This invention relates to a process for the preparation of a novel fluoran compound.

DESCRIPTION OF THE INVENTION N- ()ll lIO- 2 C.llt

COOH

Formula I Formula II 3 Rg/ i C H C a s 1 9 8 Formula III wherein R and R each represents an alkyl group having from one to five carbon atoms.

DETAILED DESCRIPTION OF THE INVENTION The fluoran compound of the formula III prepared by the process of this invention is almost colorless but when the compound is brought into contact with an electron acceptor material such as a solid acid, for example, bentonite, zeolite, acid clay, and magnesium trisilicate, or an acidic organic material, for example, benzoic acid, benzene sulfonic acid, or naphthol, the compound is immediately colored red. Further, before the fluoran compound of the formula III is brought into contact with the electron acceptor material, the compound is stable to atmosphere and light and is neither colored nor decomposed when the compound is exposed to atmosphere or light. Also, the dye formed by the contact of the fluoran compound and the electron acceptor material is quite fast. Thus, such a compound is very useful as a color former (dye precursor) for use in pressure-sensitive copying papers or heat-sensitive copying papers.

The fluoran compound of the formula III is prepared by reacting an o-(4-dialkylamino-2-hydroxybenzoyl)benzoic acid and p-phenylphenol in the presence of a condensing agent. Suitable condensing agents are sulfuric acid (about 50 to 98%), phosphorus n ox'd o l hos horic acid,a cl zi chlor'd The foflo zviri gexai' nples are giv n to iflustrat e fhe mvention without limiting the spirit and scope of the invention.

EXAMPLE 1 l5 .7 g of o-( 4-diethylamino-2-hydroxybenzoyl)benzoic acid and 8.5 g of p-phenylphenol were dissolved in 30 cc of of sulfuric acid and they were reacted for 3 hours with heating. The reaction product liquid was poured into ice water and the salt of the dye, thus deposited, was neutralized with an aqueous sodium hydroxide solution. The neutralized product was then dissolved in toluene and be concentrating the toluene solution under a reduced pressure after washing it with water, 14.0 g of the almost colorless crystals of 3diethylamino-7-phenylfluoran having a melting point of 2 l 6 2 1 8 C. was obtained.

EXAMPLE 2 ingtheformula R2 2 9 cm, 1 o s o wherein R and R each represents an alkyl group having from one to five carbon atoms.

* II k 

